Trailer with four wheel steering and independent suspension

Abstract

A trailer having a frame extending along a longitudinal axis and having a front end and a rear end, a steering linkage coupled to the frame, a pair of front wheel assemblies coupled to the front end of the frame, and a pair of rear wheel assemblies coupled to the rear end of the frame. Each wheel assembly includes a wheel carrier having a pivot member pivotally coupled to the frame along a steering axis, the wheel carrier being coupled to the steering linkage so that actuation of the steering linkage pivots the wheel carrier about the steering axis, and a wheel rotatably coupled to the wheel carrier along a wheel axis. The wheel axis is oriented approximately perpendicular to the steering axis, and the wheel axis is offset from the steering axis.

1. A trailer comprising:
 (a) a frame extending along a longitudinal axis, the frame having two sides, a front end and a rear end; 
 (b) a steering linkage coupled to the frame; 
 (c) a pair of front wheel assemblies coupled to the front end of the frame and a pair of rear wheel assemblies coupled to the rear end of the frame, wherein each of the wheel assemblies is spaced laterally outwardly from one of the sides of the frame, and each of the wheel assemblies comprises:
 (i) a wheel carrier comprising a pivot member pivotally coupled to the frame along a steering axis, the wheel carrier being coupled to the steering linkage so that actuation of the steering linkage pivots the wheel carrier about the steering axis; and 
 (ii) a wheel rotatably coupled to the wheel carrier along a wheel axis, the wheel axis being oriented approximately perpendicular to the steering axis, wherein the wheel axis is offset from the steering axis; 
 
 (d) wherein the steering coupled to each of the wheel assemblies such that when the wheels are oriented along the longitudinal axis, the wheel axis of each of the front wheel assemblies is offset from the steering axis in a forward direction relative to the steering axis, and the wheel as of each of the rear wheel assemblies is offset from the steering axis in a backward direction relative to the steering axis. 
 
     
     
       2. The trailer of  claim 1 , wherein the wheel carrier of each wheel assembly comprises:
 (a) a suspension arm pivotally coupled to the pivot member along a suspension axis; 
 (b) a shock absorber extending between the suspension arm and the pivot member, the shock absorber being configured to dampen pivotal motion of the suspension arm about the suspension axis; and 
 (c) a wheel spindle extending from the suspension arm so as to rotatably couple the wheel to the wheel carrier, the wheel spindle defining the wheel axis so that the wheel axis is offset from the suspension axis. 
 
     
     
       3. The trailer of  claim 2 , wherein the suspension axis is parallel to the wheel axis. 
     
     
       4. The trailer of  claim 2 , wherein wheel axis is located between the suspension axis and the shock absorber. 
     
     
       5. The trailer of  claim 1 , wherein the wheel carrier of each wheel assembly comprises a wheel spindle extending from the pivot member so as to rotatably couple the wheel to the wheel carrier, wherein the wheel spindle defines the wheel axis. 
     
     
       6. The trailer of  claim 1 , wherein the frame include at least one longitudinal frame member extending along the longitudinal axis, a front cross-member extending across the longitudinal frame member at the front end of the frame, and a rear cross-member extending across the longitudinal frame member at the rear of the frame, wherein the front cross-member has two ends extending outward from opposite sides of the longitudinal frame member and the front wheel assemblies are directly coupled to the ends of the front cross-member, and wherein the rear cross-member has two ends extending outward from opposite sides of the longitudinal frame member and the rear wheel assemblies are directly coupled to the ends of the rear cross-member. 
     
     
       7. The trailer of  claim 6 , wherein the longitudinal member has two ends at the front end and the rear end of the frame respectively, and the front cross-member and the rear cross-member are attached to the ends of the longitudinal frame member. 
     
     
       8. The trailer of  claim 1 , further comprising a tow arm pivotally coupled to the front end of the frame, the tow arm having a coupling configured to couple the frame to a towing vehicle, and wherein the steering linkage comprises a plurality of interconnected linkage members, the tow arm being coupled to at least one of the linkage members, and wherein each wheel assembly is coupled to at least one of the linkage members so that, when the towing vehicle turns, the tow arm pivots about the frame and the linkage members pivot each wheel assembly about their respective steering axis so as to steer the trailer. 
     
     
       9. The trailer of  claim 8 , wherein the steering linkage is configured to provide four wheel steering. 
     
     
       10. The trailer of  claim 1 , further comprising a supporting structure attached to the frame for supporting a piece of farm equipment. 
     
     
       11. The trailer of  claim 10 , wherein the supporting structure is configured to support a combine header. 
     
     
       12. A trailer comprising:
 (a) a frame including at least one longitudinal frame member extending along a longitudinal axis, a front cross-member extending across the longitudinal frame member at a front end of the frame, and a rear cross-member extending across the longitudinal frame member at a rear end of the frame, wherein the front cross-member has two ends extending outward from opposite sides of the longitudinal frame member, and wherein the rear cross-member has two ends extending outward from opposite sides of the longitudinal frame member; 
 (b) a steering linkage coupled to the frame; 
 (c) a pair of front wheel assemblies coupled directly to the ends of the front cross-member, and a pair of rear wheel assemblies coupled directly to the ends of the rear cross-member, each wheel assembly comprising:
 (i) a wheel carrier comprising a pivot member pivotally coupled to the frame along a steering axis, the wheel carrier being coupled to the steering linkage so that actuation of the steering linkage pivots the wheel carrier about the steering axis; and 
 (ii) a wheel rotatably coupled to the wheel carrier along a wheel axis, the wheel axis being oriented approximately perpendicular to the steering axis, wherein the wheel axis is offset from the steering axis. 
 
 
     
     
       13. The trailer of  claim 12 , wherein the longitudinal member has two ends at the front end and the rear end of the frame respectively, and the front cross-member and the rear cross-member are attached to the ends of the longitudinal frame member. 
     
     
       14. The trailer of  claim 12 , wherein the wheel axis of each of the front wheel assemblies is offset from the steering axis in a forward direction relative to the steering axis when the wheels are oriented along the longitudinal axis. 
     
     
       15. The trailer of  claim 12 , wherein the wheel axis of each of the rear wheel assemblies is offset from the steering axis in a backward direction relative to the steering axis when the wheels are oriented along the longitudinal axis.